It is well-known in the art to apply thin coatings of fluid material by sprayed techniques utilizing pneumatic sprays, roller-coating, brush-coating, and the like. Such devices can apply thin coatings of fluids, either in the liquid form, such as adhesives, paint or the like, or in the solid or semi-solid state, such as pellets, beads and the like.
The present invention relates to that kind of applicator which utilizes a plurality of bristles in a brush-like configuration which is agitated so as to flick small droplets of the material-to-be-coated from a supply source to the object to be coated.
Such devices may be in a bristle-brush form in roll or cylindrical configuration, or bristle-brush form in an upstanding array which, when agitated, flicks the pellets, droplets, beads or mist from the edge of the bristles onto the target or subject to be coated.
Devices of this nature have been disclosed in U.S. Pat. No. 3,735,929 dated May 29, 1973 and titled "DEVICE FOR APPLYING A SELECTED MOISTURE CONTENT TO A WEB MADE OF A FIBROUS MATERIAL" as well as in German patent DE 2,925,026 published Jun. 21, 1979 and titled "FIBROUS WEB DAMPENER USES WATER-STEAM MIXTURE". These prior art patents fail, however, to teach how the extremely fine and uniform coating of droplets may be applied to the target material in a high-speed, efficient and economical manner.
The following comments with regard to other prior art patents are relevant:
U.S. Pat. No. 5,097,791 discloses only a bristle brush rotating in a container of fluid and the centrifugal force is utilized to throw the fluid off the tips of the bristles. It discloses no windage control mechanism.
Canadian Patent 627480 is used to spray plaster on the walls, and likewise uses only the centrifugal force to throw the material away from the roll. There is no windage control mechanism.
German Patent 24686 discloses a bristle brush rotating against a counter roller which, itself, rotates in a pan of fluid, but which does not include any windage control mechanism.
Similarly, French Patent 986250 shows counter-rotating bristle brush and fluid applicator roll, but with no windage control mechanism.
U.S. Pat. No. 629,513 discloses a spraying device for paints, but has no pickup roller.sub.-- and merely flicks the paint from the tips of the bristles as the bristle roll is rotated by hand.
U.S. Pat. No. 694,106 utilizes rotating discs in a fluid pan with a splash plate. It has a cover but no windage control mechanism.
U.S. Pat. No. 1,588,062 shows a pickup roll, a mating roll, as well as temperature control, but has no reference to brush windage control, or any other means to control windage.
U.S. Pat. No. 1,753,251 shows a rotating brush dipped into a pan which sprays in a random pattern with a portion of the spray being discharged through a nozzle. It claims to be a novel atomizer, but it shows no windage control mechanism.
U.S. Pat. No. 1,801,830 discloses a brush rotating in a trough to spray fluid as it passes an object, but does not show any windage control mechanism.
French Patent 514,478 illustrates a pickup roll rotating in the bath of oil, from which a bristle brush picks up the fluid and flicks the oil against a passing object as the bristles are interrupted by a stationary blade. It shows no windage control mechanism.
U.S. Pat. No. 2,946,516 uses rotating discs for spraying fluid. A second rotor with discs acts against the first roller but does not have any bristles, and indeed does not have any windage control mechanism.
U.S. Pat. No. 1,882,439 shows no cover over the rotating bristle brush, and no windage control mechanism whatever.
U.S. Pat. No. 2,199,093 shows a device which applies dye material to a fabric in spotted pattern. It has a flexible paddle wheel which strikes against a stationary member. It has no pickup roll, nor does it have any windage control mechanism.
Canadian Patent 360,069 discloses a pan with fluid and a pickup roll rotating against a slowly turning brush with heavy bristles. In this disclosure, the bristles flick the liquid as a result of the roughness of the rotating pickup roll, but shows no windage control mechanism.
U.S. Pat. No. 3,873,025 is entirely different, inasmuch as there is no brush roll whatever. It discloses a spreader roll which transfers the fluid to another roll, and it is only the centrifugal force between the two rolls which causes the fluid to be discharged. There is no windage control whatever.
U.S. Pat. No. 2,291,046 discloses a mechanism for supplying fuel oil to a furnace. Air is forced through and around the brush and into the fire through a nozzle with the fuel droplets well dispersed. However, there is no windage control device disclosed.
British Patent 1,339,916 shows a mechanism quite similar to the device of the present invention, but does not discuss, disclose, or make any claims about controlling air currents for uniformity and mist-control, and has no windage control device.